propers: add June's collect and antiphon text

Real collect text for all 16 June saints that have one, plus a real
antiphon for 4 of them and a fifth (Ss. Peter and Paul) that deliberately
reuses the Chair-of-Peter-at-Antioch antiphon text, matching the source's
own cross-reference — same extraction method as prior months.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/data/propers/common/commemoration-of-st-paul-collect.yml

@@ -0,0 +1,18 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617) — read
+# directly from the reference engine's own real-date output (2035-06-30).
+# Same convention as data/propers/temporal/*-collect.yml.
+id: commemoration-of-st-paul-collect
+text:
+  la: |
+    Orémus.
+    Deus, qui multitúdinem géntium beáti Pauli Apóstoli prædicatióne docuísti: da nobis, quǽsumus; ut, cujus natalícia cólimus, ejus apud te patrocínia sentiámus.
+    Per Dóminum nostrum Jesum Christum, Fílium tuum: qui tecum vivit et regnat in unitáte Spíritus Sancti, Deus, per ómnia sǽcula sæculórum.
+    ℟. Amen.
+  en: |
+    Let us pray.
+    O God, Who, through the preaching of the Blessed Apostle Paul, hast caused the light of the Gospel to shine gloriously among the Gentiles, we beseech thee that we who keep the Feast of his birth, may, now that he is with thee, feel to our comfort that his prayer availeth much with thee.
+    Through Jesus Christ, thy Son our Lord, Who liveth and reigneth with thee, in the unity of the Holy Ghost, God, world without end.
+    ℟. Amen.
+status:
+  la: verified
+  en: verified